The invention relates generally to plastic intake pipes for internal combustion engines, and more specifically to a method for closing an opening in a plastic intake pipe with a cover having a shape adapted thereto.
Plastic intake pipes for internal combustion engines are generally known. To produce plastic intake pipes, cores, which are held by a holding device, are in most cases coated by extrusion. Openings, produced during the manufacturing process, remain in the plastic intake pipes after the cores are removed. The openings must be closed for proper functioning. It is known that these openings are circular and are closed by correspondingly developed covers formed from a thermoplastic plastic by friction welding or ultrasonic welding. It must, however, be noted in this connection that the properties of such plastic intake pipes when in use are quite unsatisfactory. The previously known plastic intake pipes are particularly sensitive to excess pressure which is present in the intake pipe when, for instance, the combustion pressure backfires into the intake pipe due to irregularities in the combustion of the internal combustion engine. In this case, the covers are frequently no longer held fast in the opening and this adversely affects the properties relating to the use of the internal combustion engine.
The present invention is directed to providing a plastic intake pipe and a method for closing the openings therein such that the above-mentioned disadvantages no longer occur. The intake pipe is to withstand an excess pressure that may occur when the combustion pressure backfires into the intake system.